I think I have a bad fuel pump on a B&S 16HP single cylinder engine - model 326437. I think have eliminated possible issues with fuel flow, fuel filter, etc.

The fuel pump is part 390818, but B&S also lists a repair kit - part # 394462.

Does anyone know what is involved with repairing one of these pumps, if this pretty much always fixes the problem, and how difficult it is to do? Or should I just get a new pump which is about twice the cost of the repair kit (about $60 vs $32 on a piece of equipment I only paid $100 for)? Also, the nipple from the fuel pump which connects to the rubber tube going to the oil fill tube came out when I was removing the tube, It seemed to go back into the pump pretty snugly - but wondering if that should be a consideration in whether to get new pump vs. repairing?

Make sure that that nipple is tight in the pump,if that's for the line that goes to the crankcase,that's how the pump gets the vacuum pulse from the engine to make it work.Other than that,the pumps are very easy to rebuild,all you have are a couple of rubber gaskets/diaphragms and springs that create the pulse in the fuel pump.Be careful when you take it apart,there are one or two small springs that you need to get back in the right place,if there is a separate gasket and diaphragm then you need to get them in the correct order when you put it back together.Also make sure that the fuel passages are clean sometimes they will get a little dirt in them that will restrict the fuel flow.

Thanks for advice. Before I do the fuel pump repair, is there any way to check the existing pump internally to make sure it is the problem, or maybe make adjustments or repairs that do not require the repair kit? I was also able to get the same fuel pump from another engine and try it and it did not work either (but the second pump had not been used for quite a few years and may be defective also). Do these pumps usually go out suddenly, which seemed to be the case with mine?

If the diaphragm tears or gets a hole in it,it will stop pumping but it would also stop pumping if it lost the vacuum pulse from the crankcase or if the rubber line coming from the crankcase gets a hole in it.Most times,they won't work after sitting for a while,the gas evaporates,the diaphragm gets hard and won't pump,usually in a case like that,they'll start pumping again if you wet the diaphragm with gas or wd40 to soften it,occasionally they're just stretched to far to pump though.On the older carburetors that had the fuel pump on them,a rebuild included surfacing the plates to insure they were flat so they sealed good but most of the newer pumps are plastic,I've never had one that didn't seal good but I guess that could be a possibility also.

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